Blasting method and apparatus



June 15, 1937. R. w. DULL 2,083,695

BLASTING' METHOD AND APPARATUS Filed May 27, 1935 Patented June 15, 1931 S PATENT OFFICE BLASTING METHOD AND APPARATUS Raymond W. DnlLLa Grange, IlL, assignor to Safety Mining Company, a corporation of Illinois Application May 27, 1933, Serial No. 673,148

19 Claims.

been developed. The present invention aims to provide a new method for the application of high 15 pressure air or other gases to the breaking down of coal and other materials and also to provide certain advantageous improvements in the apparatus heretofore suggested for this general purpose.

20 Referring to the drawing,

Figure 1 is a general view illustrating the application of the apparatus to coal mining,

Fig. 2 is a view in longitudinal section through one form of cartridge according to the present invention,

Figure 3 is a view in longitudinal section I through a modified form of cartridge for accomplishing the purposes of the present invention.

Referring first to Figure 2, it will be observed 30 that the cartridge may consist of a steel body 1 having an internal charge receiving chamber which is closed at one end of the cartridge by a cap member 8. The oppomte end of the cartridge may be of solid construction in which there is pro- 35 vided a plurality of radially arranged discharge ports ii. A valve controlled opening ll serves to place the interior of the cartridge in communication with the discharge ports I! under appropriate conditions. The opening H is in the form of a 40 conical valve seat designed for cooperation with a correspondingly formed valve it carried on one end of a rod I2. The opposite end of rod I2 is provided with a piston which fits slidably within the internal bore formed in the cartridge. The 45 can 8 is provided with an axial port ll designed to be placed in communication with a high pressure air supply pipe 3, which may be coupled to the cap member 8 by the elements 8 and Ill.

The piston may be thought of as dividing the 50 bore in which it moves into a charge receiving space (that to the left of the piston in each figure) and a control chamber or space-the space at the rightof the piston.

The principle of operation of this form of cartridge will b described before proceeding with a description of the alternative form of cartridge and of the method according to which these cartridges are employed. Assuming the pipe 3 to be connected to a suitable source of high pressure air or other gas, it will be observed that the first effect of the introduction of air into the cartridge through the port II will be to exert a considerable pressure on the head surface of the piston, thereby moving the same, together with the valve rod and valve member l3 in an axial direction 10 and bringing the valve it into firm sealing engagement with the surface It. This having been accomplished, which, of course, occurs instantaneously, the high pressure air somewhat gradually passes around the piston into the main charge receiving chamber of the cartridge. It should be mentioned in this connection that the piston is somewhat loosely fitted to the bore within the cartridge in order that the high pressure air introduced in advance of the piston may gradually pass to the opposite side thereof to build up in the main chamber a full charge of air. After a charge of the desired volume and pressure has been introduced into the main chamber of the cartridge, it is intended that the piston be operated to unseat the valve is, thereby permitting the escape of the entire charge through the discharge ports I! and into the surrounding material to be broken down. This is accomplished in an exceedingly simple manner, by merely reducing the pressure in the small chamber of the cartridge in advance of the piston. Thus, by venting the pipe 3 to the atmosphere, the small volume of gas in advance of the piston readily escapes through the port II and pipe 3 into the atmosphere, thus causing'an instantaneous drop in pressure in the small chamber in advance of the piston. This, of course, gives rise to a differential pressure condition wherein the pressure on the remote side of the piston greatly exceeds that oh the opposite side, thereby resulting in a rapid axial movement of the piston in a direction to remove the valve I! from its seat. This is followed, of course, by the practically instantaneous escape of the entire volume of high pressure air through the several discharge ports II into the surrounding material to be broken down.

There is shown in Figure 3 a modified form of cartridge designed to operate on precisely the same principle as described in connection with 50 Figure 2. In this case the cartridge with its discharge ports, its end. cap and supply pipe and pipe connections, are exactly the same as in Figure 2 and are designated by similar reference numerals. The entire difference between the two 1 devices lies in the form of the piston and its valve. The shank I6 is tapered at one end to form a valve to correspond to valve l3 in the above described construction and at its opposite end is provided with a piston. In this case, however, the piston is suitably packed by means of cup leathers 20 and retaining rings 2|. Disposed within the piston is a supplemental valve member IT designed for sealing engagement as indicated at I8 on a ring member IS. A spring 23 serves to normally maintain the valve member I! in sealing engagement with ring IS. A plurality of ports 22 provide communication from one side of the piston to the other when valve member I! is in open position.

The operation of the device illustrated in Figure 3 is as follows: Assuming the pipe 3 to be connected to a source of high pressure air, the first result of the passage of air from pipe 3 through port II and into the small chamber 25 in advance of the piston is to move the entire piston assembly axially in a direction to close the valve at the discharge end of the cartridge. When the piston has reached the limit of its movement in this direction, the continued building up of pressure in the chamber 25 will result in opening of the valve l1 against the action of spring 23, thereby permitting high pressure air to pass directly from chamber 25 through ports 22 into the maincharge containing chamber 24. When a charge of desired volume and pressure has been introduced into the chamber 24, the supply of air through pipe 3 may be discontinued, under which condition the piston will remain in position to maintain the valve at the discharge end of the cartridge in firm sealing engagement. This may be explained by the fact that the area of the piston subjected to high pressure air contained in chamber 25 is substantially greater than that area of the piston which is subjected to pressure from chamber 24. It should .also be noted that the pressure in chamber 25 will normally be greater than that in chamber 24 by an amount substantially equal to pressure required to open valve I'l against the action of spring 23. It is apparent that if the pressure contained in chamber 25 were suddenly released to the atmosphere, the piston would immediately be moved by the pressure existing in chamber '24 in a direction to open the valve at the discharge end of the cartridge and prevent unrestricted escape of the high pressure air from chamber 24 outwardly through the radial discharge ports. This is precisely the manner in which the discharge of the cartridge is brought about both in this case and in the case of the construction illustrated in Figure 2.

Referring now to Figure 1, there is illustrated a coal face 2, suitably undercut and drilled and provided with a cartridge l of the character illustrated in either Figures 2 or 3 and a supply pipe 3 extending from the cartridge to a compressor 4. It will be understood in this connection that the compressor 4 would normally be located in a safe position entirely out of line with the coal face to be broken down. In the supply pipe 3 there is provided a valve 5 and a pressure gauge 6, the latter, of course, indicating at all times the degree of pressure which has been introduced into the cartridge. In one position of the valve 5 high pressure, air is free to pass from the compressor 4 through pipe 3 to the cartridge, while in another position of the valve 5 the fiow of high pressure air from the compressor 4 is completely cut on and the pipe 3 is vented to the atmosphere. A suitable lateral discharge 5' may be provided for venting the pipe 3 to the atmosphere when the valve is so adjusted.

From the foregoing description it should be evident that the present invention provides a form of cartridge which may be discharged at will at any desired pressure ranging from slightly in excess of zero up to the maximum pressure capacity which may be developed by an air compresson Moreover, it should be realized that the method herein presented provides an arrangement wherein the cartridge may be so discharged at any desired pressure by merely operating valve 5 to cut ofl the flow of air from the compressor and to vent the pipe 3 to the atmosphere when such desired pressure has been reached as indicated by the pressure gauge 6. This method provides a degree of flexibility not heretofore obtainable with any method of blasting or breaking down material in that each individual shot may be made at a pressure designed to accomplish precisely the amount of work which that shot has to do. In the blasting of coal, for example, it often happens that after a number of holes have been drilled and shots appropriately placed, the shooting of one or more of such shots may leave but very little work to be done by those shots remaining to be fired, and in such a case the present method offers the ability to accurately gauge the amount of force applied to the work to be done. It is also important to note that the mechanics of the cartridge used under this method need not be as accurately executed as would be required if such a cartridge were to remain charged for any considerable length of time. For example, a slight leakage of the valve at the discharge end of the cartridge, is, under the present method, of very little consequence, inasmuch as such leak would occur only during the time when high pressure air was being introduced in the cartridge at a relatively rapid rate and the cartridge would be discharged immediately upon the attainment of a charge of the desired pressure. Mention should also be made of the fact that the cartridge may remain connected to the supply pipe 3 and be thus used for shooting any desired number of shots. It is contemplated that the supply pipe 3 will be in the form of a suitable armored flexible tubing capable of safely carrying extremely high pressures. Thusithe cartridge does not involve any item of expendable supplies other than compressed air and does not involve the making and breaking of connections each time the cartridge is discharged and prepared for recharging. There is provided in efl'ect a relatively permanent service unit capable of performing a vast amount of useful work in an accurately controlled manner and at the expense only of the necessary volume of high pressure air or other gas.

The apparatus described provides a further possibility not heretofore mentioned and not obtainable with many known methods of blasting. Thus, with the present apparatus it is entirely possible to discharge two or more cartridges simultaneously without any possibility of one or more of a series of such connected cartridges failing to discharge. The venting of a single supply pipe feeding the high pressure air to two or more cartridges would serve to discharge. each of said cartridges without possibility of failure owing to an instantaneous reduction in pressure in the control chamber of each cartridge by the venting of the common supply pipe connected thereto.

In most other forms of blasting devices there are variable factors which preclude dependable shooting of two or more cartridges simultaneously.

It should be understood that the invention is not restricted to theparticular units or details of construction shown. The source of high pressure air may be other than an air compressor and the form of the discharge mechanism within the cartridge may be widely varied.

I claim:

1. A material breaking apparatus comprising a source of compressed gas, a supply pipe extending therefrom to the material to be broken, a cartridge connected to said supply pipe and adapted to be positioned in or adjacent the material to. be broken, said cartridge embodying a differential valve controlling the release of compressed gasfrom said cartridge into the material to be broken, said valve being actuated into closing position by the introduction of compressed gas into said cartridge through said supply pipe and being actuated into open position when the flow of gas is reversed, and means for cutting oil the fiow of gas from said source and reversing the flow of gas in said supply pipe, thereby effecting release of the compressed gas from said cartridge into the material to be broken.

2. The method of breaking coal or other materials including the positioning therein of a receptacle for the reception of a. charge of compressed gas, introducing therein a charge of compressed gas, and efiecting release of the charge of compressed gas at the will of the operator at any desired pressure through control of the supp y- 3. Means'for providing a supply of gaseous fluid under pressure, conducting means therefrom, a receiving chamber for the compressed gas having associated therewith means for releasing the gas including 'a valve, and means controlled by the pressure in said conducting means for controlling said valve, and means associated with said conducting means for permitting variation of the pressure therewithin at the will of the operator.

4. Means for providing a supply of gaseous fluid under pressure, a conducting means extending therefrom, a cartridge positioned in material to be broken and connected to said conducting means to receive therethrough a charge of compressed gas, and means interposed in said conducting means between said supply and the cartridge for effecting discharge of the cartridge.

5. A method of breaking down material which comprises the following steps; introducing into the material to be broken a container for receiving a blasting charge, charging the container when so placed to any desired blasting pressure from a remote point and effecting under remote control the discharge of the blast in the material at the operators will and irrespective of the particular blasting pressure then existent.

6. A material breaking apparatus comprising a source of blasting pressure, a cartridge for receiving a blasting charge of any desired value. means for conducting pressurefrom said source to said cartridge, means' operable at will regardless of the pressure in the cartridge for closing said supply means, and means operable at will regardless of the pressure in the cartridge, provided said pressure be substantially above atmospheric, for releasing the blasting charge.

7. In a blasting apparatus, a container for receiving a blasting charge, means for charging said container to any desired blasting pressure,

- andmeans utilizing the pressure of the blasting charge for eflecting release of the blasting charge irrespective of the particular blasting pressure in said container.

8. In a blasting apparatus, a blasting cartridge for receiving a blasting charge, a source of blasting pressure, means for conducting blasting pressure from said source to said cartridge, means under operator control for closing off said conducting means from said pressure source and for reducing the pressure in said conducting means, and means responsive to said pressure reduction for effecting discharge of the blast from the cartridge.

9. In a blasting apparatus, a blasting cartridge for receiving a blasting charge, a source of blasting pressure, a pipe line for conducting pressure from said source to said cartridge, valve means for cutting off flo'w'of pressure through saidpipe line and for venting "said pipe line, and means responsive to. said venting for effecting release of the blasting charge from the cartridge.

'10. In a blasting apparatus, a cartridge having a container for receiving a blasting charge, discharge means for said container, a valve for controlling said discharge means, a differential piston for actuating said valve and for holding said valve closed, means for conducting pressure to said container to act on the larger pressure area of said piston to hold said valve closed, valve means carried within the piston for conducting pressure past said piston to the container to act on the opposed reduced area of said piston, said valve means closing automatically upon reverse in flow of the pressure, and means 11. In a blasting apparatus, a cartridge having I a container for receiving a charge of blasting pressure, a discharge orifice therefor, a valve for closing said orifice, a difierential piston for con-.

trolling said valve, means for introducing pressure into said container, the pressure acting on the larger pressure area of the piston to maintain said valve closed, the pressure fiowing past the piston to the container at the other side of the piston, and means for venting the container to reduce the pressure acting on the larger area of the piston so that the pressure in the container acting on the reduced piston area effects movement of the piston to open said valve.

12. In a blasting cartridge, a container for receiving a blasting charge, discharge means therefor, means for charging the container, and means controlled by the charging pressure for maintaining said discharge means closed, and means for eifecting release of said discharge means at will.

13. A method of blasting down material which comprises the following steps: introducing into the material a means for confining blasting pressure, supplying to said means, when the latter is in position in the material to be broken down. blasting pressure from an extraneous point, and effecting upon the attainment of substantially any desired superatmospheric pressure in said the charge into the material from the confining means.

15. In a blasting apparatus, a container for receiving a blasting charge, discharge means therefor, means for charging the container, and means controlled by the charging pressure for maintaining said discharge means closed, and means for effecting release of said discharge means at will, including a vent valve remote from said container.

16. A material breaking device comprising a cartridge body having a charge receiving chamber therein and a discharge orifice, a valve controlling said oriflce, means associated with said cartridge and operative on supply of pressure to said cartridge to close said valve and maintain the same closed and on venting of pressure to cause valve opening to release the charge, and means for supplying from a point extraneous to the cartridge receiving hole and venting to a point extraneous to said cartridge receiving hole fluid pressure relative to said cartridge.

17. A material breaking device consisting of a cartridge provided with a chamber adapted to be charged with compressed gas from a source of supply, means embodied in the cartridge and operable at will for efiecting repeated charging and discharging thereof, and means remotely positioned relative to the cartridge for controlling said operation of the aforesaid means.

18. The method of breaking coal or other materials including the positioning therein of a receptacle for the reception of a charge of compressed gas, introducing into said positioned receptacle a charge of compressed gas, which charge is divided in the receptacle into a control fraction and a blasting fraction, and effecting release of the blasting fraction of the charge at the will of the operator by venting from the receptacle the control fraction.

l9. A blasting cartridge comprising a container adapted to be charged with a compressed fluid at blasting pressure and having an orifice through which said fluid may be discharged, and a fluid pressure controlled valve for retaining the pressure in said container and for releasing the pressure consisting of a single movable part for governing said orifice.

RAYMOND W. DULL. 

